Phonograph



. June 17, 1930. E. E. PINKERTON PHON GRAPH 2 sheeis-sheet 1 ,Filed Nov. 5, 1925 Vzw/W4' a/Wa//a/ kfw/740 /4 .une 17,` 1930. E. E. PINKERTON 1,764,977

PHONOGRAPH Filed Nov. 5, 1925 2 sheets-'sheet 2 /2 [j] I 1N @-1.0 and arrangements 'of srarss EEN EDWARD E. PINKERTGN, F CHICAGO, ILLINOIS i PHONOGRAPH Applie'auon mea November 5, 192s. serial No. 672,702.

' My invention yrelates to improvements in phonographs; and has for its object the provision of animproved construction of this character capable of reproducingV records g5 Without material orconfusing scratching sounds-andgenerally improving the quality of the tone of the phonograph. l `Other objects 4will appeark hereinafter. f The invention consists in the combinations i parts hereinafter describe'da'nd-claimed. f The invention will be best understood by reference to" theV accompanying drawings formin'gapart of this specification, and in .415 which f Fig. l is` a front view of a phonograph sound boxy embodying the invention;

Fig. 2, a partial section taken substantially on line 2 2 of Fig. 1;

3, a partialsection taken of Fig. 1; n l Fig. 4; a similar view to Fig.` 1 but showing a modified form of construction;

Fig. 5,' a sectional view of the construction on line shown in Fig. 4';

e Fig.` 6, a sidevview of the construction shown'A in'Fig. 4;` I

Y Fig. 7, a sectional view taken on line 7 7 -of Fig. 5; 4

6 0 'Fig.'8, aside view of another modified form of construction, p Fig. 9, a section takenon line 9-9 of Fig. 8 and vfFig' 10,V a sectional View of'another modifi- 35 cation.

The VVpreferred `form of construction as illustrated in the drawingscomprises the-usual sound box 10 mounted on the end of the usual tone arm .10 Tand equipped with the usual dia- ,v4.9 phragm 11. The sound box 10 also carries the usualineedle arm 12-pivoted at 13 thereon and carrying at one end the usual needle 14 and secured `at the other end to the diaphragm 11 at 15. So much of the construc- 11'5 tion is old and well known constituting the usual and common form of sound boxes for phonographs, the same constituting no part of my present invention except in so far as it co-operates with the construction and parts 59 to be presently described.

A spring wire tension rod 16 is passed under the needle arm 12 and through perforated ears 17 secured to the rim of the sound box on opposite sides of the needle arm as shown. Adjusting nuts 18 are threaded on the ends of the tension rod 16 and serve as means for adjusting the tensionlin said rod. The perforations in the ears 17 are somewhat higher than the under edge of the needle arm 12so that tightening the nuts 18 introduces tension into both the needle arm 12 and the diaphragm 11 tending to bulge the diaphragm 11 outwardly as indicated b v the dotted lines in Fig. 3.1 This tension in the diaphragm 11 and in the needle arm 12 takes up and prevents any lost motion in either or in the connection between them so that there can be no undue rattling or vibration of either and the only vibrations transmitted to the diaphragm are the vibrations caused by the undulations or'sound waves in the phonograph record. In this way scratching or other confusingand discordant vibrations are eliminated or lessened-or softened and the quality and tone of the phonograph is ment of the clips 19 as indicated by the dotted lines in Fig. 4. The inner edge 22 of the needle arm k12 is inclined as shown so that adjustment of the tension rod 2O toward or away from the periphery of the sound box exerts greater or less outward tension on the needle arm and consequently greater or less outward tension on the diaphragm so that by simply sliding the clips 19`on the periphery of the sound box the tension in both the needle arm and diaphragm may be adjusted as desired. The clips 19 are also provided with hooks or points 23 and by means of which a tension member in the form of a gutstring may be substituted for the wooden bar 20, the ends of the'string being looped about or otherwise secured to the points 23.

In the form of construction illustrated in Figs. 8 and 9 a supporting lug or arm 24 is secured to the sound box 10 projecting parallel with the needle arm 12. A perforated band 25 is fitted over the ends ofthe needle arm 12 being held in place by the usual set screw 25 which passes freely through a perforation provided in said'band. The band 25 is provided with a threaded stem 26 passing through a perforation in the end of the lug 24 and an adjusting nut 27 is threaded on the end of stem 26 and whereby the outward tension rod in the needle arm and dia hragm maydbe readily applied and as desire In Fig. 10 I have illustrated the construction disclosed inv Figs. 5, 6 and 7 with a gut string 28 employed forproducing the tension in the needle arm and diaphragm, said string being pro ed with knots 29 engaging`v the projections 23 on the clips 19. It will be found that this arrangemmt constitutes a very simple and eiective one for the purpose and one which imparts a very clear and mellow tonel to the instrument.

" :The clips 19 are rotatably located on opposits sides of the periphery of the sound box so that portions of each clip are on the extremities of a 'diameter of said sound box.

. 'It will now be noted that whenthe clips are revolved about the 'periphery of the sound box the tension element 20 will .impinge against the converging-under, side of the needle arm 12 to anextent dictated by the -amount of the rotation of the clips. lIt will be obvious that when the tension element is i in contact with that point'of the under side of the needle arm which is nearest to the diaphragm 11, the stressy on the needle arm along the diaphragm is at its greatest. It is of course to be understood that. both the clips are rotated to an equal degree and in the same direction.

By'careful rotation of theclips intermediate degrees of adjustment of the diaphragm, via the needle arm, can be obtained. It will also be observed in the form illustrated in Fig. 5. 6, 7 and 10, that it will be possible to adjust the needle arm 12 by pushing the clips 19 away from the operator, in the position shown in Fig. 10, thus bending the cat gut strip 28 about the downwardly projecting bend in the middle of the needle arm 12 as a fulcrum. AFurther slipping of the clips will cause a pressure on' the needle arm 12 tending to raise the downwardly projecting bend which joins the diaphragm at its center, and consequently to raise or bulge the diaphragm 17 itself in an upward or outward direction.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without de arting from the spirit of the invention. I, t erefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the eeopeei the appended-.icleima I, H

Having described my invention, what I claim asnew and desire to secure by Letters Patent is:

1. The combination with a sound box of a phonograph having a diaphragm, of a needle arm pivotally mo v tedon said sound box and having a bend operatively'l connected with said diaphragm; clips sli bly mounted on the rim of said box; and atension m mounted on said clips and passing under impingingagainst an inclined part of said needle arm whereby adj t of said varies Lthe tension on said needle am stantia-lly as.desci'ibed. f E; ,p

2. The combination with sound boxof a phonograph having s diaphragm, 0f' I needle 'um pivotally `on said sound ai box and having a bend o vely with saidi diaphragm; chpssldebl on the rimof said box; mndaexi le 2.; i. string secured to said elips'rmd .se under and impinging a ed pui of gainst an inc l said needle'arm whereby adjustment of seid clips varies the tension oi seid needle arm, substantially as described.

3. The combination with'e sound box of a phonograph having a diaphngm and a needle armoperatively connected therewith., A of Aa exble tension member traversing said sound box andipassingnnder and impnging against an inclined partei said to exert outward tension thereon, substalb muy as dageraad:Y l

4. The combination with' l sound box of a phonograph havinga diaphragm and a needle arm operativel connected therewi l operoratedclips s byenge' ther'im @im of said sound box; and an e member passing under against an inclined part of said needle erin and through the Perfex-ations in said clips,v the ends `of said elongated tension mnnibr being secured to said clips, and said clips being sldably ad' ble on the rim of said sound bo`x to adjust said elgiiated tension member relatively to said n le arm, sub stantiallyV as described. In testimony whereof I have signed my name to this specifi 

